Conveyor chains with one or more article carrying members are well known in the prior art. For examples: Lynch U.S. Pat. No. 1,707,088 shows solid cylindrical rods extending to one side of successive roller chain links with each rod having a reduced shank in the form of a pintle that acts as a link pin in the chain; Talbott U.S. Pat. 4,129,206 shows a similar link pin and rod with a scored sleeve, for receiving an empty can, extending outward of a hub rotatably mounted on the rod; Tracy U.S. Pat. No. 4,501,351 shows similar rods extending to one side of occasional special roller chain links wherein each rod pintle is plugged into a hollow link pin and the rod is coupled to an adjacent extended regular link pin by a supplemental link plate that is fastened substantially flush against an interconnected regular outer pin link plate by a cotter pin through the regular link pin; and Michalik U.S. Pat. No. 4,388,990 shows a modified roller chain wherein each link pin extends uniformly beyond the outer pin link plate to one side of the chain and solid cylindrical extension rods are connected to and aligned with occasional pins by means of split sleeves or bushings which will open to release the extension rods should an obstruction occur in the conveyor path. There is also a known commercially available variation of the Tracy patent structure (produced by a division of the patent assignee, Incom International Inc.) wherein the pintle is eliminated and a hollow rod is press fitted to the end of one extended regular link pin and coupled to an adjacent extended link pin by a cotter pin and a supplemental link plate that is mounted flush with the rod end.
A disadvantage of the aforedescribed prior art, with the exception of the Michalik patent, is that the rods, which are spaced in accordance with the particular conveyor installation to carry items suspended to one side of a single chain conveyor, are made essentially integral with the chain and risk damage to the chain, such as a chain break or detachment from the chain drive, should something obstruct movement of the rods or articles carried thereby. Since these chains are usually utilized to transport articles between and through processing stations, such obstructions do occur; and additionally significant routine forces are imparted to the rods at the processing stations. In the Talbott patent structure the sleeve is weakened to break free outwardly of the supporting rod but the chain is not fully protected thereby. While the structure of the Michalik patent overcomes, to a degree, the risk of chain damage, it involves a significant risk that the split sleeve will open to release the carrying rod when subjected to routine processing forces or that it will gradually allow the rod to slip away during repeated cycles through processing operations. The latter risk is further increased if there is even a slight difference between the cross sections of the link pin and an extension rod aligned therewith because one will tend to hold open the split sleeve respecting the other. The present invention overcomes the deficiencies of the structure described by Michalik.